Update:Issue is resolved on DMP-BD30 ONLY with firmware v1.6.
There is currently no resolution for Denon 2500 or DMP-BD10.What is the issue?
The LFE channel (the .1 in 5.1 or 7.1) for PCM output over HDMI is 5db lower than it should. This applies to any tracks internally decoded to PCM or native PCM track on the disc.

What is a LFE?
The LFE or Low Frequency Effect is channel that contains frequencies below 120Hz. It is the ".1" in 5.1 or 7.1 tracks. It contains sounds designed to go exclusively to the sub woofer.

Is analog affected?
No. Analog does not appear to be affected. The output leaving the mixer is -5db but the LFE channel is amplified 5db after DAC (digital to analog conversion) so it is at the proper level.

Is SPDIF (digital out, optical out) affected?
No. This only affect PCM output on the LFE channel. PCM is limited to 2 channels (Left & right) over SPDIF. There is no LFE output to be affected.

Is bitstream output affected?
No. Bitstream output which is sending the raw compressed track is not affected. DD, DTS, DD+, TrueHD, DTS-HD, DTS-HD MA tracks are NOT affected if the player output is bitstream. Regardless of the player settings LPCM tracks are always sent as PCM so LPCM tracks on a BD disc output over HDMI will always be affected.

So if I have player set to bitstream to a compatible receiver (Onkyo-705) I am not affected?
No. LPCM tracks on the disc are output as PCM regardless of player settings. Since they are output as PCM they will be affected. There is currently no player setting to bypass the issue when playing a PCM track.

Can't I just boost the LFE channel +5db on my AVR (receiver)?
Virtually all AVR only allow lowering the LFE channel not raising it. If you AVR has a +5db setting it could compensate but I am not aware of any AVR that has such a setting. This is not the same thing as boosting the sub (see next questions).

Can't I just boost the subwoofer output +5db on my AVR (receiver)?
Not if you are using any bass management. Most HT setups redirect bass below a certain cutoff (40Hz, 60Hz, 80Hz) from main speakers to the subwoofer. Boosting the sub +5db will make the LFE channel have proper level but now the redirected bass from other 5 or 7 channels is now running "+5db too hot".

I am not using any bass management (speakers set to "large"). Can I boost subwoofer output +5db?
Yes. If the AVR is not applying ANY bass management then all bass from main channels goes to main speakers. There is no redirected bass, only the LFE channel goes to the subwoofer. The sub should be raised +5db for LPCM tracks and set to normal on all other tracks. For bass management to be turned off all speakers must be able to handle full range as main channels routinely have bass <40Hz. With bass management that bass is redirected to the subwoofer. If bass management is turned off and speakers can't handle the low frequency then sound quality will be negatively affected.

I want accurate channel balance. What can I do?
For the Panasonic DMP-BD30 download and install firmware version 1.6 or later. The issue has been confirmed resolved with firmware 1.6.

There are "workarounds" for the other two players until a fix is made available. Each has a drawback. Also if you have speakers set to "large" (full range) then you can also raise/lower SW output (see above).

On Denon 2500 ONLY lower other channels in player menu:
In player setup change all the channels except the LFE to -5b. The LFE should be left at +0db. Since the LFE is already incorrectly lowered 5db now all the channels will have the same level. The settings only affect PCM output so bitstream is not negatively affected. The overall film volume level for PCM output will now be 5db lower and can be compensated by turning up volume 5b on AVR. You can not used this workaround on the Panasonic players. While they have the level options in player setup menu they only affect the analog output not PCM over HDMI.

On DMP-BD10 ONLY use analog output for PCM tracks:
Connect the player via 6 channel analog out to AVR. All tracks except PCM should be bitstream by HDMI normally. For PCM tracks switch to analog input. The speaker distances, levels, and crossovers will need to be set in player as most AVR do not apply any DSP logic to analog in.

Is there a simple workaround to get bass response that is "close"?
While not a true fix or workaround some members have been raising SW output 2-3db. You will not want to raise SW level +5db if using bass management as this will cause SW to run "too hot". The LFE level will be correct but all redirected bass will be +5db. Setting SW level +2db or +3db is a compromise. The LFE output will be 2-3db too low and redirected bass will be 2-3 too high. Understand this is not a 100% accurate fix but rather a method to boost SW response to compensate for LFE drop without over compensating.

I don't notice this issue with my player. Are you sure it is affected?
If your player is one of the affected players then you have the bug. It isn't a player build issue but rather a design issue that affects all players of that model. Stating 100% that a player is not affected without doing a comparison to another player is not possible. If during a point in the movie the LFE channel hits 85db, then 80db will be output. A viewer has no way to know the track is 85db. Without a frame of reference how can it be determined that 80db is right or too low? It may be possible to say "it doesn't bother me", "even with the bug output is good" but saying the bug doesn't exist is simply wrong.

What about using Analog output (thanks Krisjan)?
The 6 channel analog output is NOT affected by the LFE issue. PCM tracks can be output properly over analog out. However player can not decode DD+,TrueHD, DTS-HD, DTS-HD MA tracks for output over analog out.

The analog output can be used for PCM tracks only and the HDMI output used for all other tracks via bitstream. Since the issue only affects PCM over HDMI (which isn't being used) all outputs will be accurate.

While the LFE bug is "fixed" by using Analog outputs, analog has it's own set of limitations. The largest is that analog out is only 6 channel which can not output 7 & 8 channel tracks. Most AVR can not matrix 5.1->7.1 speakers via analog input. Bass management needs to be done in the player as most AVR will not apply any logic to analog inputs. Bass management in player may not be as capable as AVR. Some AVR apply room balancing, speaker distance calculations that exceed those offered in player (Audessey processing on Onkyo). You will need to switch input on AVR for each movie (analog in for PCM tracks, HDMI in for all others).

Just curious, how was it or [by who] confirmed that the analogs are not affected?

Also how do we know that the uncompressed signal enters the "mixer" when the secondary audio is set to off [as it should be] to avoid such manipulation in the first place? [Same goes for the +5db boost after DA conversion] I'm not saying it doesn't or can't but I wonder where your info on this comes from, or is it just a theory at this point?

Is the LFE encoded 5db lower on all the discs, so it is the player's proper job to raise it?

Audiosceptics accept audio trials using 25 people. A recent Oxford study with over 353,000 patient records from 639 separate clinical trials shows for every 1,000 people taking diclofenac or ibuprofen there would be 3 additional heart attacks, 4 more cases of heart failure and 1 death every year.

Just curious, how was it or [by who] confirmed that the analogs are not affected?

Also how do we know that the uncompressed signal enters the "mixer" when the secondary audio is set to off [as it should be] to avoid such manipulation in the first place? [Same goes for the +5db boost after DA conversion] I'm not saying it doesn't or can't but I wonder where your info on this comes from, or is it just a theory at this point?

The issue has nothing to do with the encoding. It's about the decoding within the player.

So, as previously pointed out, LFE leaving the mixer is -5db, and that is the incorrect step?

Audiosceptics accept audio trials using 25 people. A recent Oxford study with over 353,000 patient records from 639 separate clinical trials shows for every 1,000 people taking diclofenac or ibuprofen there would be 3 additional heart attacks, 4 more cases of heart failure and 1 death every year.

What is the issue?
The LFE channel (the .1 in 5.1 or 7.1) for PCM output over HDMI is 5db lower than it should. This applies to any tracks internally decoded to PCM or native PCM track on the disc.

What is a LFE?
The LFE or Low Frequency Effect is channel that contains frequencies below 120Hz. It is the ".1" in 5.1 or 7.1 tracks. It contains sounds designed to go exclusively to the sub woofer.

Is analog affected?
No. Analog does not appear to be affected. The output leaving the mixer is -5db but the LFE channel is amplified 5db after DAC (digital to analog conversion) so it is at the proper level.

Is SPDIF (digital out, optical out) affected?
No. This only affect PCM output on the LFE channel. PCM is limited to 2 channels (Left & right) over SPDIF. There is no LFE output to be affected.

Is bitstream output affected?
No. Bitstream output which is sending the raw compressed track is not affected. DD, DTS, DD+, TrueHD, DTS-HD, DTS-HD MA tracks are NOT affected if the player output is bitstream. Regardless of the player settings LPCM tracks are always sent as PCM so LPCM tracks on a BD disc output over HDMI will always be affected.

So if I have player set to bitstream to a compatible receiver (Onkyo-705) I am not affected?
No. LPCM tracks on the disc are output as PCM regardless of player settings. Since they are output as PCM they will be affected. There is currently no player setting to bypass the issue when playing a PCM track.

Can't I just boost the LFE channel +5db on my AVR (receiver)?
Virtually all AVR only allow lowering the LFE channel not raising it. If you AVR has a +5db setting it could compensate but I am not aware of any AVR that has such a setting. This is not the same thing as boosting the sub (see next questions).

Can't I just boost the subwoofer output +5db on my AVR (receiver)?
Not if you are using any bass management. Most HT setups redirect bass below a certain cutoff (40Hz, 60Hz, 80Hz) from main speakers to the subwoofer. Boosting the sub +5db will make the LFE channel have proper level but now the redirected bass from other 5 or 7 channels is now running "+5db too hot".

I don't notice this issue with my player. Are you sure it is affected?
If your player is one of the affected players then you have the bug. It isn't a player build issue but rather a design issue that affects all players of that model. Stating 100% that a player is not affected without doing a comparison to another player is not possible. If during a point in the movie the LFE channel hits 85db, then 80db will be output. A viewer has no way to know the track is 85db. Without a frame of reference how can it be determined that 80db is right or too low? It may be possible to say "it doesn't bother me", "even with the bug output is good" but saying the bug doesn't exist is simply wrong.

So running the speakers large if they are capable of low bass and boosting the subwoofer level would compensate?
On the same line would setting the crossover to 40Hz would minimize the issue?

The thing that would alarm me the most is that the issue exists even when the player is set to bitstream. This says that there is no way to get a native PCM track out without the player putting its dirty paws on it to apply processing I'm specifically trying to avoid by using bitstreaming in the first place.

Does this imply that the player is applying bass management to native PCM tracks even when set to bitstream?

Do other players apply processing to a native PCM track when the player is set to bitstream? Maybe this is actually also part of the design bug in this player.

So running the speakers large if they are capable of low bass and boosting the subwoofer level would compensate?

I don't like the term "large" because it can vary from AVR to AVR. If your AVR applies 0 bass management (i.e all sound from 20Hz to 20KHz on main channels is sent to main speakers). Then yes +5db on the subwoofer will compensate exactly because only the LFE is -5db and the sub is ONLY playing the LFE channel.

Quote:

On the same line would setting the crossover to 40Hz would minimize the issue?

All depends on the track (how much <40Hz signal in main channels) and it likely will vary from track to track.

I have my crosssovers set to 80Hz on all channels. I find a boost of "about 2-3db" is a good starting point.

The problem is that once bass management is applied any boost will vary from track to track and is a "best guess" only.

Panasonic & Denon need to fix this issue. An all digital mistake is easy to spot & fix. These are $500-$1000 players with digital output not $30 Daewoo with analog stereo out.

Others have tested as well. I wish we were making this up but no one is.

Your last comment was unnecesarry there are plenty of misinformation on these boards, I was simply looking for info here that has credibility which those from Roger qualifies as such, so thanks for the links.

What I don't get is, and Roger may explain this, it's obvious that Panasonic "corrupts" the signal but not by design but rather just a "mistake" somewhere, as I can't imagine this was done intentionally, so all they need is to "undo" the mistake. But so far there is no word what the source of the problem, only the symptoms. Now that Denon is reportedly has the same issue, it seems they just dressed up and re badged the BD30 and sell it for double. Not the first time they have done this, maybe to avoid the embarrassment, they lend a helping hand to Panasonic to solve this quickly? One can hope.

Some background: The PCM LFE signal is supposed to be 10dB down compared to the other PCM signals. It is recorded that way so that explosions and stuff can be carried in the LFE channel without clipping during transmission to the AVR and initial processing in the AVR. This is also true about analog LFE sent to an AVR over multi-channel analog connections. A properly designed AVR boosts the LFE back up the necessary 10dB before adding in any bass steered to the subwoofer from the main speakers and sending the combo out to the subwoofer.

If bass steering happens inside the player (prior to multi-channel analog output from a player equipped that way), then you have cases where the LFE is sent over to the AVR as 15dB down to account for the extra bass that may have been contributed from main speaker channels during that bass steering in the player. What it looks like is happening is that these particular players are dropping the LFE coming in off the disc that extra 5dB INCORRECTLY.

For more background on this whole LFE issue, see this thread from the Audio Theory forum here.

Note that the 10dB lower LFE, and the boosting of it back to normal in the AVR, is nothing new. It has been this way essentially forever in traditional DD5.1 and DTS for example.

When you send such a bitstream to the AVR, the LFE encoded within the bitstream is already 10dB down, but the AVR boosts it during the decode. Since these players are not decoding such bitstreams before sending them to the AVR, there is no place for them to make the mistake of dropping the LFE the erroneous, extra 5dB.

When you send PCM to the AVR the LFE is supposed to be 10dB down, and the AVR is supposed to boost it back up again prior to mixing with steered bass and sending the result to the subwoofer. But the AVR is not expecting an ADDITIONAL 5dB drop in the LFE coming from the player. Apparently these players are doing this both to raw PCM tracks and to PCM resulting from decoding bitstreams inside the player.

Depending upon the signal path architecture it may be easier or harder for them to eliminate this bogus 5dB drop.
--Bob

Depending upon the signal path architecture it may be easier or harder for them to eliminate this bogus 5dB drop.

Well that's just it,the signal supposed to be untouched, if the secondary decoder is set to off. I don't even know why it even enters into the mixer as it's been stated, it really should just bypass everything....

If bass steering happens inside the player (prior to multi-channel analog output from a player equipped that way), then you have cases where the LFE is sent over to the AVR as 15dB down to account for the extra bass that may have been contributed from main speaker channels during that bass steering in the player. What it looks like is happening is that these particular players are dropping the LFE coming in off the disc that extra 5dB INCORRECTLY.

Yes that's one theory I was thinking about too. It's almost like the player's bass management is activated, which would yield the -15db output at least on the analog outputs, but it shouldn't affect the digital ones.One more reson why the digital signal shouldn't enter into ant DSP chip on board unless selected by the user.

Well that's just it,the signal supposed to be untouched, if the secondary decoder is set to off. I don't even know why it even enters into the mixer as it's been stated, it really should just bypass everything....

Likely a design "flaw". If the PCM can pass through mixer without being affected then "why" design another bypass mode. Obviously it isn't passing through the mixer with no effect but likely in the design it made sense ($$$) to not have a bypass mode where PCM "goes around the mixer".

Likely a design "flaw". If the PCM can pass through mixer without being affected then "why" design another bypass mode. Obviously it isn't passing through the mixer with no effect but likely in the design it made sense ($$$) to not have a bypass mode where PCM "goes around the mixer".

They not designing another bypass mode, since there isn't one to begin with.
BTW if Toshiba could create such path with FW update, and by doing so turning the whole HD DVD platform upside down, Panasonic could have done this, much easier when they designed the player. But to be honest if it must enter into the mixer but comes out unchanged, I would settle for that too.

If I understand correctly, someone with a crossover at 120 can defeat the problem by setting the sub gain in the AVR to +5 as then all redirected bass is properly boosted?

No. If the crossover is set to 120Hz then ALL bass below 120Hz gets redirected from the mains to the SW. +5db on the sub will make the LFE channel correct but now ALL the redirected bass is running 5db too hot.